Using phenological cameras to track the green up in a cerrado savanna and its on-the-ground validation

Author(s)

Alberton, Bruna ^[1] ; Almeida, Jurandy ^[2] ; Helm, Raimund ^[3] ; Torres, Ricardo da S. ^[4] ; Menzel, Annette ^{[3, 5]} ; Cerdeira Morellato, Leonor Patricia ^[1]

Affiliation

^[1] UNESP Univ Estadual Paulista, Dept Bot, Phenol Lab, Inst Biociencias, BR-13506900 Rio Claro, SP - Brazil

^[2] Fed Univ Sao Paulo UNIFESP, Inst Sci & Technol, BR-12231280 Sao Jose Dos Campos, SP - Brazil

^[3] Tech Univ Munich, Ctr Life & Food Sci, D-85354 Freising Weihenstephan - Germany

^[4] Univ Campinas UNICAMP, Inst Comp, RECOD Lab, BR-13083852 Campinas, SP - Brazil

^[5] Tech Univ Munich, Inst Adv Study, D-85748 Garching - Germany

• Document type: Journal article
• Source: ECOLOGICAL INFORMATICS; v. 19, p. 62-70, JAN 2014.
• Web of Science Citations: 36

Abstract

Plant phenology has gained new importance in the context of global change research, stimulating the development of novel technologies for phenological observations. Regular digital cameras have been effectively used as three-channel imaging sensors, providing measures of leaf color change or phenological shifts in plants. We monitored a species rich Brazilian cerrado savanna to assess the reliability of digital images to detect leaf-changing patterns. Analysis was conducted by extracting color information from selected parts of the image named regions of interest (ROIs). We aimed to answer the following questions: (i) Do digital cameras capture leaf changes in cerrado savanna vegetation? (ii) Can we detect differences in phenological changes among species crowns and the cerrado community? (iii) Is the greening pattern detected for each species by digital camera validated by our on-the-ground leafing phenology (direct observation of tree leaf changes)? We analyzed daily sequences of five images per hour, taken from 6:00 to 18:00 h, recorded during the cerrado main leaf flushing season. We defined 24 ROIs in the original digital image, including total or partial regions and crowns of six plant species. Our results indicated that: (i) for the studied period, single plant species ROIs were more sensitive to changes in relative green values than the community ROIs, (ii) three leaf strategies could be depicted from the species' ROI patterns of green color change, and (iii) the greening patterns and leaf functional groups were validated by our on-the-ground phenology. We concluded that digital cameras are reliable tools to monitor high diverse tropical seasonal vegetation and it is sensitive to inter-species differences of leafing patterns. (C) 2014 Elsevier B.V. All rights reserved. (AU)

• FAPESP's process: 10/51307-0 - Floristic diversity and seasonal patterns of rupestrian fields and cerrado
• Grantee: Leonor Patricia Cerdeira Morellato
• Support Opportunities: Research Grants - Research Partnership for Technological Innovation - PITE
• FAPESP's process: 10/52113-5 - e-phenology: the application of new technologies to monitor plant phenology and track climate changes in the tropics
• Grantee: Leonor Patricia Cerdeira Morellato
• Support Opportunities: Research Program on Global Climate Change - Regular Grants